Conventionally, storage apparatuses for recording information by using the hologram principle are known. A hologram is formed on a recording medium by interference between reference light and object light. During reproduction, original information is reproduced by entering reference light, which has the same wavelength and angle as those during writing, into the hologram.
A hologram storage medium is characterized in high density and large capacity. Further, multiplexing recording of information can be performed by changing the angle of reference light or changing the wavelength of the reference light, and this can further increase the density. While conventional electronic storage apparatuses sequentially read information, information can be read from a hologram in parallel at once. This can achieve high data processing. Such a hologram reproducing apparatus is disclosed in, for example, Patent Document 1.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2001-93157